Ann Peters, a doctor at the Longevity Medical Clinic in Gold River, Calif., prescribes HGH for “age management” purposes, and says her patients report improved vision with hormone therapy. These results usually occur in her older patients.

Is it possible that this hand-eye benefit is purely psychological?

Unlikely, says Gaffney. When drugs are tested, “placebo responders” do arise—people who feel a medicine’s good effects even when they’re not given the medicine. But these effects are fleeting.

“When you get a ‘miracle cure’ or placebo response, it usually doesn’t last more than a few days,” Gaffney says. “I would find it hard to believe that a psychological benefit would be sustained over a grueling baseball season.”

Why didn’t George Mitchell just measure players’ head sizes to find HGH users?

“I have found no evidence that exogenous HGH increases your skull size,” Gaffney says. “There is a condition called acromegaly, a growth associated with a tumor in the pituitary gland that enlarges the feet, hands, and jaw. As I ask colleagues who have worked with hormone replacement and HGH, they haven’t said that HGH increases skull size.”

But what about Barry Bonds’ seemingly sprouting noggin?

“When you look at Barry Bonds’ increase in hat size, it’s not all that impressive,” he says.

Gaffney says that adema, a growth of muscles through the neck, could give the illusion that players’ heads have grown. They might also have swollen muscles in their face, which creates another illusion of head growth.

What risks are involved with abuse of HGH?

Cancer, for one. Because HGH can spur the growth not just of muscle, but of tumors, the Longevity Clinic’s Peters won’t prescribe hormone therapy to anyone with active cancer, or even a family history of the disease.

“If you are even worried about cancer, I would not recommend it,” she said. “If you’re prediabetic, it’s not recommended—those with a glucose resistance are non-candidates.”

Peters says HGH can also cause your blood pressure to rise, can make you retain fluid, and can cause body aches, especially in the joints. These effects increase with larger doses that doctors would prescribe, she says.

Since steroid and HGH use only helps those who are willing to work(the drugs alone don't build muscle), some argue that they’re not all bad. True?

Gaffney says the counterargument to this optimistic take on P.E.D.s arises from their addiction-related effects.

“Because you’re going to have testosterone withdrawal when you discontinue the drugs, anabolic steroids are—I wouldn’t say addicting, but they’re habit-forming,” he says. “Your body will want to pick up the testosterone again.”

Months of research into the history of these drugs has given Assael a philosophical take.

“Steroids meet at the crossroads of optimism and avarice,” he says. “They are drugs of optimism because they don’t work unless you put in the work. But the work you put in can quickly turn into avarice—you don’t just want to be bigger, you want to be the biggest.”

It’s like a smoldering fire. It’s very hard to stop yourself, and when you can’t control it, you catch fire,” he continues. “There was an inevitable progression to the grotesque, because it is, literally, an arms race. That’s what happened in baseball. That’s why deterrence became a necessity.”